MYSQL2PSQL - MySQL to PostgreSQL Migration Tool

Tool for converting mysql database to postgresql. It can create postgresql dump from mysql database or directly load data from mysql to postgresql (at about 100 000 records per minute).

It can translate now most data types and indexes, but if you experience some problems, feel free to contact me, I’ll help you.


Mysql2psql is packaged as a gem. Install as usual (use sudo if required).

$ gem install mysql2psql
NB: the gem hasn't been formally released on yet. For now you need to clone the git repo at and 'rake install'

After installation, the “mysql2psql” command will be available. When run, it will generate a default configuration file in the current directory if a config file is not already found. The default configuration filename is mysql2psql.yml.

$ mysql2psql

You can use an alternate config file by passing the filename/path as a parameter:

$ mysql2psql ../another/world.yml

Running Migrations

See the configuration file for documentation about settings. Key choices include:

  • whether to dump to a file, or migrate direct to PostgreSQL

  • migrate only the schema definition, only the data, or both schema and data

After editing the configuration file and launching tool, you will see something like..

Creating table friendships...
Created table friendships
Loading friendships...
620000 of 638779 rows loaded. [ETA: 2010/01/21 21:32 (00h:00m:01s)]
638779 rows loaded in 1min 3s
Indexing table friendships...
Indexed table friendships
Table creation 0 min, loading 1 min, indexing 0 min, total 1 min

Database driver dependencies

Mysql2psql uses the ‘mysql’ and ‘pg’ gems for database connectivity. Mysql2psql gem installation should automatically install these too.

If you encounter any issues with db connectivity, verify that the ‘mysql’ and ‘pg’ gems are installed and working correctly first. The ‘mysql’ gem in particular may need a hint on where to find the mysql headers and libraries:

$ [sudo] gem install mysql -- --with-mysql-dir=/usr/local/mysql

NB: With Ruby 1.8.x, the gem install will usually complain about “No definition for …” errors. These are non-fatal and just affect the documentation install. This doesn’t happen with Ruby 1.9.2.

Getting the source

Mysql2psql was first produced by Max Lapshin <[email protected]> who maintains the master repository at

The gem packaged version you are currently looking at has yet to be merged into the master repo. The gem bundling and refactoring for testing was done by Paul Gallagher <[email protected]> and the repository is at

Running tests

If you fork/clone the project, you will want to run the test suite (and add to it if you are developing new features or fixing bugs).

A suite of tests are provided and are run using rake (rake -T for more info)

rake test:units
rake test:integration
rake test

Rake without parameters (or “rake test”) will run both the unit and integration tests.

Unit tests are small standalone tests of the mysql2psql codebase that have no external dependencies (like a database)

Integration tests require suitable mysql and postgres databases to be setup in advance. Running the integration tests will rewrite data and schema for the “mysql2psql_test” databases in mysql and postgres. Don’t use this database for anything else!

mysql on localhost:3306

  • database created called “mysql2psql_test”

  • user setup for “mysql2psql” with no password

  • e.g. mysqladmin -uroot -p create mysql2psql_test mysql -uroot -p -e “grant all on mysql2psql_test.* to ‘mysql2psql’@‘localhost’;” # verify connecction: mysql -umysql2psql -e “select database(),‘yes’ as connected” mysql2psql_test

postgres on localhost:5432

  • database created called “mysql2psql_test”

  • role (user) access setup for “mysql2psql” with no password

  • e.g. psql postgres -c “create role mysql2psql with login” psql postgres -c “create database mysql2psql_test with owner mysql2psql encoding=‘UTF8’” # verify connection: psql mysql2psql_test -U mysql2psql -c “c”

Notes, Limitations, Outstanding Issues..


  • more tests

  • release gem

  • a windows cmd shim

note from mgkimsal

I’m still having trouble with bit(1)/boolean fields workaround I’ve found is to put output in file then in VIM on file, search/replace the true/false binary fields with t/f specifically

(reversed on 3/23 - should be ^A gets f) :%s/^@/t/g :%s/^A/f/g keystrokes are ctrl-v ctrl-shift-@ to get the ‘true’ binary field keystrokes are ctrl-v ctrl-shift-A to get the ‘false’ binary field


Project founded by Max Lapshin <[email protected]>

Other contributors (in git log order):